/Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Selection/MeshTopologySelectionMechanic.h
The best-guess 3D frame for the current select
[FFrame3d](API\Runtime\GeometryCore\TFrame3) GetSelectionFrame ( bool bWorld, [FFrame3d](API\Runtime\GeometryCore\TFrame3) * InitialLocalFrame ) const